Optoelectronic integrated structures are fabricated to have photonic devices with different optical properties. Often such devices are fabricated using materials that either strongly interact with guiding light through one of an absorption/gain process for photon signal detection, or which allow guided light to propogate with minimal attenuation, such as in a waveguide. The conventional manner of achieving these different results is to use different elements and materials in differing spatial locations in the optoelectronic integrated circuit. In group III-V photonic integrated circuits, materials such as In1-x Gax As1-y Py of varying mole fractions can be employed for this purpose. In silicon-based optoelectronic integrated circuits other materials such as germanium or alloys thereof are utilized in combination with silicon. The integration of different materials in different regions in an optoelectronic integrated structures can add significantly to the cost and complexity of fabrication.
It would be desirable to provide a low cost and easily integrated optoelectronic integrated structure in which the same optical material can, in some regions, provide an optical device which functions as signal detector having associated high signal attenuation, and other regions as a low loss waveguide.